Mapping and identification of vectors responsible for mangrove suppression in the southern bahia lowlands, brazil

Abstract

The mangrove ecosystem represents 8% of the entire coastline of the planet and occupies a total area of 181,077 km2. Brazil is the second largest country in terms of mangrove areas, second only to Indonesia. The aim of the present study was to map and identify the main vectors responsible for the suppression of mangrove cover in the Southern Lowlands of Bahia, Brazil, from Landsat satellite images available for the period 1994-2017. based on supervised classification using the Maxver method. The accuracy of the classification obtained was verified through field truth, Global Accuracy indices, and kappa and Tau agreement coefficients. The classes that presented larger coverage area in the analyzed period were: Dense ombrophilous vegetation, agriculture, exposed soil and mangrove. Two main vectors responsible for the suppression of mangrove forests were identified: The disorderly expansion of urban areas (especially the municipality of Valença) and the advance of clandestine shrimp farming due to the installation of shrimp farms without due environmental licensing process (mainly in the municipality of Nilo Peçanha). The use of geotechnologies, especially Remote Sensing and Geographic Information Systems, were fundamental tools in the identification of these vectors responsible for the suppression of mangrove areas in the study area of the Southern Bahia Lowlands.